Various processing devices, for example, graphics processing units (GPUs) have been developed to assist in the expedient display of video. Typically a two-dimensional (2D) and/or three-dimensional (3D) engine will render video as a series of video frames of data.
Real-time playback of video is typically performed at a rate of thirty (30) frames per second (fps). In various situations, such as fast forward playback, it is desirable to speed up the playback of video, but still view 30 frames per second in order to maintain compatibility with the existing infrastructure such as the various display devices, decoders, Internet browser plug-ins, etc. For example, if it is desired to speed up playback by 10% over the normal real-time playback speed, the content of 33 frames of video needs to be played back in the time allocated for 30 frames. One conventional method to achieve a 10% accelerated playback rate is to skip one frame out of every 11 frames so that only 10 of each 11 frames of video are displayed at the 30 fps rate.
Another conventional method is to perform a frame rate conversion such that for each set of 11 video frames, the first frame reflects the actual data of one of the video's frames and the next nine frames are fabricated frames through the use of interpolation of the video data of the following ten frame of the video. The interpolation of video frame data provides relatively smooth motion as compared with simply skipping method. The interpolation-type of conversion, however, typically would be performed by a very costly motion-compensated frame rate conversion algorithm.
Over the years, resolution factors have increased from DVD resolutions (720×480 pixels) to HDTV (1920×1080 pixels). Playback devices can be required to handle video frames having a full bit stream at 1920×1080 or higher, for example, to support various movie playback formats. Also playback devices can have multiple concurrent video stream processing requirements, for example, to support picture in picture (PIP) capability. Although the conventional simple frame skipping method can be adapted for such devices, the time and processing complexity needed to perform the conventional interpolation method for smoother accelerated playback referenced above becomes prohibitive, if it is even able to be done.